jobs.c

操作系统源代码

/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)jobs.c	5.1 (Berkeley) 3/7/91";
#endif /* not lint */

#include "shell.h"
#if JOBS
#include "sgtty.h"
#undef CEOF			/* syntax.h redefines this */
#endif
#include "main.h"
#include "parser.h"
#include "nodes.h"
#include "jobs.h"
#include "options.h"
#include "trap.h"
#include "signames.h"
#include "syntax.h"
#include "input.h"
#include "output.h"
#include "memalloc.h"
#include "error.h"
#include "mystring.h"
#include "redir.h"
#include <sys/types.h>
#include <fcntl.h>
#include <signal.h>
#include <errno.h>
#ifdef BSD
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#endif
#if POSIX
#include <sys/wait.h>
#endif



struct job *jobtab;		/* array of jobs */
int njobs;			/* size of array */
MKINIT short backgndpid = -1;	/* pid of last background process */
#if JOBS
int initialpgrp;		/* pgrp of shell on invocation */
short curjob;			/* current job */
#endif

#ifdef __STDC__
STATIC void restartjob(struct job *);
STATIC struct job *getjob(char *);
STATIC void freejob(struct job *);
STATIC int procrunning(int);
STATIC int dowait(int, struct job *);
STATIC int waitproc(int, int *);
STATIC char *commandtext(union node *);
#else
STATIC void restartjob();
STATIC struct job *getjob();
STATIC void freejob();
STATIC int procrunning();
STATIC int dowait();
STATIC int waitproc();
STATIC char *commandtext();
#endif


 
#if JOBS
/*
 * Turn job control on and off.
 *
 * Note:  This code assumes that the third arg to ioctl is a character
 * pointer, which is true on Berkeley systems but not System V.  Since
 * System V doesn't have job control yet, this isn't a problem now.
 */

MKINIT int jobctl;

void
setjobctl(on) {
	int ldisc;

	if (on == jobctl || rootshell == 0)
		return;
	if (on) {
		do { /* while we are in the background */
			if (ioctl(2, TIOCGPGRP, (char *)&initialpgrp) < 0) {
				out2str("ash: can't access tty; job control turned off\n");
				jflag = 0;
				return;
			}
			if (initialpgrp == -1)
				initialpgrp = getpgrp(0);
			else if (initialpgrp != getpgrp(0)) {
				killpg(initialpgrp, SIGTTIN);
				continue;
			}
		} while (0);
		if (ioctl(2, TIOCGETD, (char *)&ldisc) < 0 || ldisc != NTTYDISC) {
			out2str("ash: need new tty driver to run job control; job control turned off\n");
			jflag = 0;
			return;
		}
		setsignal(SIGTSTP);
		setsignal(SIGTTOU);
		setpgrp(0, rootpid);
		ioctl(2, TIOCSPGRP, (char *)&rootpid);
	} else { /* turning job control off */
		setpgrp(0, initialpgrp);
		ioctl(2, TIOCSPGRP, (char *)&initialpgrp);
		setsignal(SIGTSTP);
		setsignal(SIGTTOU);
	}
	jobctl = on;
}
#endif


#ifdef mkinit

SHELLPROC {
	backgndpid = -1;
#if JOBS
	jobctl = 0;
#endif
}

#endif



#if JOBS
fgcmd(argc, argv)  char **argv; {
	struct job *jp;
	int pgrp;
	int status;

	jp = getjob(argv[1]);
	if (jp->jobctl == 0)
		error("job not created under job control");
	pgrp = jp->ps[0].pid;
	ioctl(2, TIOCSPGRP, (char *)&pgrp);
	restartjob(jp);
	INTOFF;
	status = waitforjob(jp);
	INTON;
	return status;
}


bgcmd(argc, argv)  char **argv; {
	struct job *jp;

	do {
		jp = getjob(*++argv);
		if (jp->jobctl == 0)
			error("job not created under job control");
		restartjob(jp);
	} while (--argc > 1);
	return 0;
}


STATIC void
restartjob(jp)
	struct job *jp;
	{
	struct procstat *ps;
	int i;

	if (jp->state == JOBDONE)
		return;
	INTOFF;
	killpg(jp->ps[0].pid, SIGCONT);
	for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
		if ((ps->status & 0377) == 0177) {
			ps->status = -1;
			jp->state = 0;
		}
	}
	INTON;
}
#endif


int
jobscmd(argc, argv)  char **argv; {
	showjobs(0);
	return 0;
}


/*
 * Print a list of jobs.  If "change" is nonzero, only print jobs whose
 * statuses have changed since the last call to showjobs.
 *
 * If the shell is interrupted in the process of creating a job, the
 * result may be a job structure containing zero processes.  Such structures
 * will be freed here.
 */

void
showjobs(change) {
	int jobno;
	int procno;
	int i;
	struct job *jp;
	struct procstat *ps;
	int col;
	char s[64];

	TRACE(("showjobs(%d) called\n", change));
	while (dowait(0, (struct job *)NULL) > 0);
	for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
		if (! jp->used)
			continue;
		if (jp->nprocs == 0) {
			freejob(jp);
			continue;
		}
		if (change && ! jp->changed)
			continue;
		procno = jp->nprocs;
		for (ps = jp->ps ; ; ps++) {	/* for each process */
			if (ps == jp->ps)
				fmtstr(s, 64, "[%d] %d ", jobno, ps->pid);
			else
				fmtstr(s, 64, "    %d ", ps->pid);
			out1str(s);
			col = strlen(s);
			s[0] = '\0';
			if (ps->status == -1) {
				/* don't print anything */
			} else if ((ps->status & 0xFF) == 0) {
				fmtstr(s, 64, "Exit %d", ps->status >> 8);
			} else {
				i = ps->status;
#if JOBS
				if ((i & 0xFF) == 0177)
					i >>= 8;
#endif
				if ((i & 0x7F) <= MAXSIG && sigmesg[i & 0x7F])
					scopy(sigmesg[i & 0x7F], s);
				else
					fmtstr(s, 64, "Signal %d", i & 0x7F);
				if (i & 0x80)
					strcat(s, " (core dumped)");
			}
			out1str(s);
			col += strlen(s);
			do {
				out1c(' ');
				col++;
			} while (col < 30);
			out1str(ps->cmd);
			out1c('\n');
			if (--procno <= 0)
				break;
		}
		jp->changed = 0;
		if (jp->state == JOBDONE) {
			freejob(jp);
		}
	}
}


/*
 * Mark a job structure as unused.
 */

STATIC void
freejob(jp)
	struct job *jp;
	{
	struct procstat *ps;
	int i;

	INTOFF;
	for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
		if (ps->cmd != nullstr)
			ckfree(ps->cmd);
	}
	if (jp->ps != &jp->ps0)
		ckfree(jp->ps);
	jp->used = 0;
#if JOBS
	if (curjob == jp - jobtab + 1)
		curjob = 0;
#endif
	INTON;
}



int
waitcmd(argc, argv)  char **argv; {
	struct job *job;
	int status;
	struct job *jp;

	if (argc > 1) {
		job = getjob(argv[1]);
	} else {
		job = NULL;
	}
	for (;;) {	/* loop until process terminated or stopped */
		if (job != NULL) {
			if (job->state) {
				status = job->ps[job->nprocs - 1].status;
				if ((status & 0xFF) == 0)
					status = status >> 8 & 0xFF;
#if JOBS
				else if ((status & 0xFF) == 0177)
					status = (status >> 8 & 0x7F) + 128;
#endif
				else
					status = (status & 0x7F) + 128;
				if (! iflag)
					freejob(job);
				return status;
			}
		} else {
			for (jp = jobtab ; ; jp++) {
				if (jp >= jobtab + njobs) {	/* no running procs */
					return 0;
				}
				if (jp->used && jp->state == 0)
					break;
			}
		}
		dowait(1, (struct job *)NULL);
	}
}



jobidcmd(argc, argv)  char **argv; {
	struct job *jp;
	int i;

	jp = getjob(argv[1]);
	for (i = 0 ; i < jp->nprocs ; ) {
		out1fmt("%d", jp->ps[i].pid);
		out1c(++i < jp->nprocs? ' ' : '\n');
	}
	return 0;
}



/*
 * Convert a job name to a job structure.
 */

STATIC struct job *
getjob(name)
	char *name;
	{
	int jobno;
	register struct job *jp;
	int pid;
	int i;

	if (name == NULL) {
#if JOBS
currentjob:
		if ((jobno = curjob) == 0 || jobtab[jobno - 1].used == 0)
			error("No current job");
		return &jobtab[jobno - 1];
#else
		error("No current job");
#endif
	} else if (name[0] == '%') {
		if (is_digit(name[1])) {
			jobno = number(name + 1);
			if (jobno > 0 && jobno <= njobs
			 && jobtab[jobno - 1].used != 0)
				return &jobtab[jobno - 1];
#if JOBS
		} else if (name[1] == '%' && name[2] == '\0') {
			goto currentjob;
#endif
		} else {
			register struct job *found = NULL;
			for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
				if (jp->used && jp->nprocs > 0
				 && prefix(name + 1, jp->ps[0].cmd)) {
					if (found)
						error("%s: ambiguous", name);
					found = jp;
				}
			}
			if (found)
				return found;
		}
	} else if (is_number(name)) {
		pid = number(name);
		for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
			if (jp->used && jp->nprocs > 0
			 && jp->ps[jp->nprocs - 1].pid == pid)
				return jp;
		}
	}
	error("No such job: %s", name);
}



/*
 * Return a new job structure,
 */

struct job *
makejob(node, nprocs)
	union node *node;
	{
	int i;
	struct job *jp;

	for (i = njobs, jp = jobtab ; ; jp++) {
		if (--i < 0) {
			INTOFF;
			if (njobs == 0) {
				jobtab = ckmalloc(4 * sizeof jobtab[0]);
			} else {
				jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
				bcopy(jobtab, jp, njobs * sizeof jp[0]);
				for (i= 0; i<njobs; i++)
				{
					if (jobtab[i].ps == &jobtab[i].ps0)
						jp[i].ps= &jp[i].ps0;
				}
				ckfree(jobtab);
				jobtab = jp;
			}
			jp = jobtab + njobs;
			for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0);
			INTON;
			break;
		}
		if (jp->used == 0)
			break;
	}
	INTOFF;
	jp->state = 0;
	jp->used = 1;
	jp->changed = 0;
	jp->nprocs = 0;
#if JOBS
	jp->jobctl = jobctl;
#endif
	if (nprocs > 1) {
		jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
	} else {
		jp->ps = &jp->ps0;
	}
	INTON;
	TRACE(("makejob(0x%x, %d) returns %%%d\n", (int)node, nprocs, jp - jobtab + 1));
	return jp;
}	


/*
 * Fork of a subshell.  If we are doing job control, give the subshell its
 * own process group.  Jp is a job structure that the job is to be added to.
 * N is the command that will be evaluated by the child.  Both jp and n may
 * be NULL.  The mode parameter can be one of the following:
 *	FORK_FG - Fork off a foreground process.
 *	FORK_BG - Fork off a background process.
 *	FORK_NOJOB - Like FORK_FG, but don't give the process its own
 *		     process group even if job control is on.
 *
 * When job control is turned off, background processes have their standard
 * input redirected to /dev/null (except for the second and later processes
 * in a pipeline).
 */

int
forkshell(jp, n, mode)
	union node *n;
	struct job *jp;